LONDON — “Boy A” is a movie about a young man desperate to exchange notoriety for anonymity.

For its star, the ability to go unnoticed may soon be a thing of the past.

Keen-eyed moviegoers may already recognize Andrew Garfield from “The Other Boleyn Girl” or “Lions for Lambs.” Now the 24-year-old actor is attracting notice for his first starring role, as a young man trying to put a murderous past behind him in the film “Boy A.” He won critical praise and a BAFTA — the British Emmy — for his compelling performance in the British film that’s opening in U.S. theaters.

In person, Garfield has something of the intensity and vulnerability he brings to the role, mixed with an engaging candor. Earnest about his craft, he’s also happy to admit to some surprising artistic inspirations.

As a child, “I was kind of obsessed with ’80s movies — Michael J. Fox movies, mostly, like ‘Teen Wolf’ and ‘Back to the Future,”’ said Garfield, sprawled on a chair in his publicist’s London office. “And all the John Hughes’ movies. That was my safe haven from a world that I didn’t like so much because it didn’t match up to what I wanted it to be in my imagination.”

Garfield is not claiming a miserable childhood. He grew up with loving and supportive parents — American father, English mother — in the leafy suburbs south of London. He’s just, he says, a sensitive guy, the kind of actor unashamed to admit he had an artistic epiphany — “I suddenly felt what art could do!” — while listening to a busker play Don McLean’s Van Gogh-inspired ballad “Vincent.”

Thrillerlike tension mixed with gentle comedyThat emotional openness gives “Boy A” its punch. Garfield plays Jack, a young man released from prison after serving many years for the murder of another child. With a new identify and the help of a determined counselor (Peter Mullan), Jack tries to build a life, aware of lurking dangers — both from his own demons and from a media eager to unmask the freed killer.

Directed by John Cowley, the movie combines thrillerlike tension — will Jack’s true identity be discovered? — with moments of gentle comedy, as he awkwardly tries to adjust to life outside prison. In one scene, a trip to a cafe causes confusion. “What,” the young man asks, “is a panini?”

The film’s potentially explosive subject matter is handled with considerable psychological subtlety. We are shown the actions of the boy who with a friend killed a 10-year-old girl, and we see Garfield’s Jack — gauche, hesitant, sweet, yet with a lingering capacity for violence.

“It’s quite a compelling journey that I have to go on,” Garfield said. “A very primal one as well — it’s a survival story.”

Garfield concedes he was apprehensive about taking on the story, adapted from Jonathan Trigell’s novel, which has parallels to the notorious real-life murder of a Liverpool toddler by two 10-year-old boys in 1993.

“But then I thought about what I saw as the greater good,” he said, “which was exploring a subject from an angle that hasn’t been explored yet, offering a suggestion to people that maybe we shouldn’t brand kids as just evil. Maybe life and human beings are more gray than just good or bad.”

Los Angeles-born Garfield — a dual U.S. and British citizen — is well-placed to take advantage of the current Hollywood vogue for British talent.

He turned to acting as an aimless teenager, found he liked it, attended London’s Central School of Speech and Drama then got his first two professional acting jobs before he’d even graduated. He landed roles on the London stage — he was an acclaimed Romeo at 21 — and British television, and then film parts.

Slideshow: Celebrity Sightings
Garfield admits to watching and re-watching classic film performances like Robert De Niro’s in “Taxi Driver,” and to being a little obsessed with Daniel Day-Lewis and his famously intense preparations for a role.

“I heard he built an oil rig in his garden for ‘There Will be Blood,”’ said Garfield with a touch of awe.

“There is an unfathomable thing that certain leading men have, like Day-Lewis and De Niro and Pacino,” he said. “There is something that will never be decoded about those people, the power that they have.”